回顾读取properties配置文件

一时失言乱红尘 2022-05-16 08:07 269阅读 0赞

**JDBCUtil.java:**

package top.hsocode.learn.pagination.util;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    import java.util.Properties;
    
    public class JDBCUtil { 
        private static String DRIVER;
        private static String URL;
        private static String USERNAME;
        private static String PASSWORD;
    
        /** * 通过读配置文件获取数据库的相关配置 */
        //静态代码块
        static {
            //用流读入properties配置文件
            //注意：这个配置文件是放在resources/db/dev目录下的，不需要通过classpath指定
            //默认在classpath下查找，加了classpath:会找不到
            InputStream is = JDBCUtil.class.getClassLoader().getResourceAsStream("db/dev/jdbc.properties");
            Properties properties = new Properties();
            try {
                properties.load(is);
                DRIVER = properties.getProperty("jdbc.driverClassName");
                URL = properties.getProperty("jdbc.url");
                USERNAME = properties.getProperty("jdbc.username");
                PASSWORD = properties.getProperty("jdbc.password");
            } catch (IOException e) {
                e.printStackTrace();
            }
    
        }
        public static Connection getConnection(){
            Connection conn = null;
            try {
    // Class.forName("com.mysql.jdbc.Driver");
    // String url = "jdbc:mysql://localhost:3306/hsoTech";
    // String username = "root";
    // String password = "root";
    // conn = DriverManager.getConnection(url, username, password);
                Class.forName(DRIVER);
                conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            return conn;
        }
    }

**jdbc.properties:**

jdbc.driverClassName=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://localhost:3306/hsoTech
    jdbc.username=root
    jdbc.password=root